Grid supported ceiling panels are very common in the office buildings where ceilings are constructed over open floor plan interior designs, such as cubicles. Such ceiling are popular in other commercial, industrial and domestic environments, including and not limited to hotels, meeting rooms, recreation rooms and other types of rooms or constructions which require removable ceilings for access to utilities (heating, air conditioning, water) that are concealed in the space between the drop ceiling tiles and the structural ceiling of the room. Such ceiling systems are well suited for use in old office buildings with high ceilings and with ceilings that are curved or arched, especially barrel vault ceilings. However most conventional suspended ceiling systems have T-shaped grid members and those members are usually exposed to view from the room.
At least one system exists which provides a ceiling panel that is installed from beneath the support grid and partially covers the exposed grid members but leaves exposed a border of approximately 6 mm (for example the Hunter Douglas system). However that system is supported in only one direction, in other words, on two of the four sides. This renders it very unsafe. When a building is shaken by an earth tremor such ceiling panels may dislodge from the support grid and fall upon and injure people or damage property. To prevent damage and injury from falling panels, such systems are often sold with safety clips that retain the panels in the support grid in case it falls and leaves it hanging from the safety clip but out of position. The installation of such safety clips must be very precise because even a small variation in its position renders it inoperative. In addition, movement of the support grid between the moment panel first calls out of the grid and before the safety clip restrains it (e.g. another tremor) may cause the clip to fail and let the panel fall.
Panels for such systems are often made of from a clad particle agglomerate (solid) of approximately 16 mm with a weight of approximately 9.8 kg/m2, implying that the panel of approximately 610×610 mm weighs approximately 3.64 kg. That is a very heavy and potentially unsafe weight when one considers that the panel is suspended above the heads of the people who live or work beneath the panels or occupy or travel through a room and that has a ceiling made of such panels. Since the prior art panels are supported on only two of their four sides, they are vulnerable to deformation because gravity is always acting on the two free sides. The weight of the panel augments the action of gravity, thereby causing the panel to deform and lose its precise retention measurements.
There is another type of ceiling panel which is a bent metal sheet hung from a support grid that has several clamps at its lower part. The bent part has a vertical shape and carries some embossing that projects from the edge for the purpose of keeping the panels secured by the clamps. That system is much more expensive than the one described above and has weight limitations, given that the design is based on the elastic strength of the steel being greater than that required for the panel to fall under gravity. In addition the system only retains the panel on two sides. When a lighting fixture is contained within the panels, the weight of the fixture deforms them.